file.c 60.6 KB
Newer Older
1
2
/*
  FUSE: Filesystem in Userspace
Miklos Szeredi's avatar
Miklos Szeredi committed
3
  Copyright (C) 2001-2008  Miklos Szeredi <miklos@szeredi.hu>
4
5
6
7
8
9
10
11
12
13

  This program can be distributed under the terms of the GNU GPL.
  See the file COPYING.
*/

#include "fuse_i.h"

#include <linux/pagemap.h>
#include <linux/slab.h>
#include <linux/kernel.h>
Alexey Dobriyan's avatar
Alexey Dobriyan committed
14
#include <linux/sched.h>
15
#include <linux/module.h>
16
#include <linux/compat.h>
17
#include <linux/swap.h>
18

19
static const struct file_operations fuse_direct_io_file_operations;
20

21
22
static int fuse_send_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
			  int opcode, struct fuse_open_out *outargp)
23
24
{
	struct fuse_open_in inarg;
25
26
27
	struct fuse_req *req;
	int err;

28
	req = fuse_get_req_nopages(fc);
29
30
	if (IS_ERR(req))
		return PTR_ERR(req);
31
32

	memset(&inarg, 0, sizeof(inarg));
33
34
35
	inarg.flags = file->f_flags & ~(O_CREAT | O_EXCL | O_NOCTTY);
	if (!fc->atomic_o_trunc)
		inarg.flags &= ~O_TRUNC;
36
37
	req->in.h.opcode = opcode;
	req->in.h.nodeid = nodeid;
38
39
40
41
42
43
	req->in.numargs = 1;
	req->in.args[0].size = sizeof(inarg);
	req->in.args[0].value = &inarg;
	req->out.numargs = 1;
	req->out.args[0].size = sizeof(*outargp);
	req->out.args[0].value = outargp;
44
	fuse_request_send(fc, req);
45
46
47
48
49
50
	err = req->out.h.error;
	fuse_put_request(fc, req);

	return err;
}

Tejun Heo's avatar
Tejun Heo committed
51
struct fuse_file *fuse_file_alloc(struct fuse_conn *fc)
52
53
{
	struct fuse_file *ff;
Tejun Heo's avatar
Tejun Heo committed
54

55
	ff = kmalloc(sizeof(struct fuse_file), GFP_KERNEL);
Tejun Heo's avatar
Tejun Heo committed
56
57
58
	if (unlikely(!ff))
		return NULL;

59
	ff->fc = fc;
60
	ff->reserved_req = fuse_request_alloc(0);
Tejun Heo's avatar
Tejun Heo committed
61
62
63
	if (unlikely(!ff->reserved_req)) {
		kfree(ff);
		return NULL;
64
	}
Tejun Heo's avatar
Tejun Heo committed
65
66
67
68
69
70
71
72
73
74

	INIT_LIST_HEAD(&ff->write_entry);
	atomic_set(&ff->count, 0);
	RB_CLEAR_NODE(&ff->polled_node);
	init_waitqueue_head(&ff->poll_wait);

	spin_lock(&fc->lock);
	ff->kh = ++fc->khctr;
	spin_unlock(&fc->lock);

75
76
77
78
79
	return ff;
}

void fuse_file_free(struct fuse_file *ff)
{
80
	fuse_request_free(ff->reserved_req);
81
82
83
	kfree(ff);
}

84
struct fuse_file *fuse_file_get(struct fuse_file *ff)
85
86
87
88
89
{
	atomic_inc(&ff->count);
	return ff;
}

90
91
92
93
94
95
96
97
98
99
100
101
102
103
static void fuse_release_async(struct work_struct *work)
{
	struct fuse_req *req;
	struct fuse_conn *fc;
	struct path path;

	req = container_of(work, struct fuse_req, misc.release.work);
	path = req->misc.release.path;
	fc = get_fuse_conn(path.dentry->d_inode);

	fuse_put_request(fc, req);
	path_put(&path);
}

Miklos Szeredi's avatar
Miklos Szeredi committed
104
105
static void fuse_release_end(struct fuse_conn *fc, struct fuse_req *req)
{
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
	if (fc->destroy_req) {
		/*
		 * If this is a fuseblk mount, then it's possible that
		 * releasing the path will result in releasing the
		 * super block and sending the DESTROY request.  If
		 * the server is single threaded, this would hang.
		 * For this reason do the path_put() in a separate
		 * thread.
		 */
		atomic_inc(&req->count);
		INIT_WORK(&req->misc.release.work, fuse_release_async);
		schedule_work(&req->misc.release.work);
	} else {
		path_put(&req->misc.release.path);
	}
Miklos Szeredi's avatar
Miklos Szeredi committed
121
122
}

123
static void fuse_file_put(struct fuse_file *ff, bool sync)
124
125
126
{
	if (atomic_dec_and_test(&ff->count)) {
		struct fuse_req *req = ff->reserved_req;
127

128
		if (sync) {
129
			req->background = 0;
130
131
132
133
134
			fuse_request_send(ff->fc, req);
			path_put(&req->misc.release.path);
			fuse_put_request(ff->fc, req);
		} else {
			req->end = fuse_release_end;
135
			req->background = 1;
136
137
			fuse_request_send_background(ff->fc, req);
		}
138
139
140
141
		kfree(ff);
	}
}

142
143
int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
		 bool isdir)
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
{
	struct fuse_open_out outarg;
	struct fuse_file *ff;
	int err;
	int opcode = isdir ? FUSE_OPENDIR : FUSE_OPEN;

	ff = fuse_file_alloc(fc);
	if (!ff)
		return -ENOMEM;

	err = fuse_send_open(fc, nodeid, file, opcode, &outarg);
	if (err) {
		fuse_file_free(ff);
		return err;
	}

	if (isdir)
		outarg.open_flags &= ~FOPEN_DIRECT_IO;

	ff->fh = outarg.fh;
	ff->nodeid = nodeid;
	ff->open_flags = outarg.open_flags;
	file->private_data = fuse_file_get(ff);

	return 0;
}
170
EXPORT_SYMBOL_GPL(fuse_do_open);
171

172
void fuse_finish_open(struct inode *inode, struct file *file)
173
{
174
	struct fuse_file *ff = file->private_data;
175
	struct fuse_conn *fc = get_fuse_conn(inode);
176
177

	if (ff->open_flags & FOPEN_DIRECT_IO)
178
		file->f_op = &fuse_direct_io_file_operations;
179
	if (!(ff->open_flags & FOPEN_KEEP_CACHE))
Miklos Szeredi's avatar
Miklos Szeredi committed
180
		invalidate_inode_pages2(inode->i_mapping);
181
	if (ff->open_flags & FOPEN_NONSEEKABLE)
Tejun Heo's avatar
Tejun Heo committed
182
		nonseekable_open(inode, file);
183
184
185
186
187
188
189
190
191
	if (fc->atomic_o_trunc && (file->f_flags & O_TRUNC)) {
		struct fuse_inode *fi = get_fuse_inode(inode);

		spin_lock(&fc->lock);
		fi->attr_version = ++fc->attr_version;
		i_size_write(inode, 0);
		spin_unlock(&fc->lock);
		fuse_invalidate_attr(inode);
	}
192
193
}

194
int fuse_open_common(struct inode *inode, struct file *file, bool isdir)
195
{
Tejun Heo's avatar
Tejun Heo committed
196
	struct fuse_conn *fc = get_fuse_conn(inode);
197
198
199
200
201
202
	int err;

	err = generic_file_open(inode, file);
	if (err)
		return err;

203
	err = fuse_do_open(fc, get_node_id(inode), file, isdir);
204
	if (err)
205
		return err;
206

207
208
209
	fuse_finish_open(inode, file);

	return 0;
210
211
}

212
static void fuse_prepare_release(struct fuse_file *ff, int flags, int opcode)
213
{
214
	struct fuse_conn *fc = ff->fc;
215
	struct fuse_req *req = ff->reserved_req;
216
	struct fuse_release_in *inarg = &req->misc.release.in;
217

218
219
220
221
222
223
	spin_lock(&fc->lock);
	list_del(&ff->write_entry);
	if (!RB_EMPTY_NODE(&ff->polled_node))
		rb_erase(&ff->polled_node, &fc->polled_files);
	spin_unlock(&fc->lock);

224
	wake_up_interruptible_all(&ff->poll_wait);
225

226
	inarg->fh = ff->fh;
227
	inarg->flags = flags;
228
	req->in.h.opcode = opcode;
229
	req->in.h.nodeid = ff->nodeid;
230
231
232
	req->in.numargs = 1;
	req->in.args[0].size = sizeof(struct fuse_release_in);
	req->in.args[0].value = inarg;
233
234
}

235
void fuse_release_common(struct file *file, int opcode)
236
{
Tejun Heo's avatar
Tejun Heo committed
237
238
	struct fuse_file *ff;
	struct fuse_req *req;
239

Tejun Heo's avatar
Tejun Heo committed
240
241
	ff = file->private_data;
	if (unlikely(!ff))
242
		return;
Tejun Heo's avatar
Tejun Heo committed
243
244

	req = ff->reserved_req;
245
	fuse_prepare_release(ff, file->f_flags, opcode);
Tejun Heo's avatar
Tejun Heo committed
246

Miklos Szeredi's avatar
Miklos Szeredi committed
247
248
249
250
251
252
	if (ff->flock) {
		struct fuse_release_in *inarg = &req->misc.release.in;
		inarg->release_flags |= FUSE_RELEASE_FLOCK_UNLOCK;
		inarg->lock_owner = fuse_lock_owner_id(ff->fc,
						       (fl_owner_t) file);
	}
Tejun Heo's avatar
Tejun Heo committed
253
	/* Hold vfsmount and dentry until release is finished */
254
255
	path_get(&file->f_path);
	req->misc.release.path = file->f_path;
Tejun Heo's avatar
Tejun Heo committed
256
257
258
259
260

	/*
	 * Normally this will send the RELEASE request, however if
	 * some asynchronous READ or WRITE requests are outstanding,
	 * the sending will be delayed.
261
262
263
264
	 *
	 * Make the release synchronous if this is a fuseblk mount,
	 * synchronous RELEASE is allowed (and desirable) in this case
	 * because the server can be trusted not to screw up.
Tejun Heo's avatar
Tejun Heo committed
265
	 */
266
	fuse_file_put(ff, ff->fc->destroy_req != NULL);
267
268
}

269
270
static int fuse_open(struct inode *inode, struct file *file)
{
271
	return fuse_open_common(inode, file, false);
272
273
274
275
}

static int fuse_release(struct inode *inode, struct file *file)
{
276
277
278
279
280
281
282
283
284
285
286
	fuse_release_common(file, FUSE_RELEASE);

	/* return value is ignored by VFS */
	return 0;
}

void fuse_sync_release(struct fuse_file *ff, int flags)
{
	WARN_ON(atomic_read(&ff->count) > 1);
	fuse_prepare_release(ff, flags, FUSE_RELEASE);
	ff->reserved_req->force = 1;
287
	ff->reserved_req->background = 0;
288
289
290
	fuse_request_send(ff->fc, ff->reserved_req);
	fuse_put_request(ff->fc, ff->reserved_req);
	kfree(ff);
291
}
292
EXPORT_SYMBOL_GPL(fuse_sync_release);
293

294
/*
295
296
 * Scramble the ID space with XTEA, so that the value of the files_struct
 * pointer is not exposed to userspace.
297
 */
298
u64 fuse_lock_owner_id(struct fuse_conn *fc, fl_owner_t id)
299
{
300
301
302
303
304
305
306
307
308
309
310
311
312
313
	u32 *k = fc->scramble_key;
	u64 v = (unsigned long) id;
	u32 v0 = v;
	u32 v1 = v >> 32;
	u32 sum = 0;
	int i;

	for (i = 0; i < 32; i++) {
		v0 += ((v1 << 4 ^ v1 >> 5) + v1) ^ (sum + k[sum & 3]);
		sum += 0x9E3779B9;
		v1 += ((v0 << 4 ^ v0 >> 5) + v0) ^ (sum + k[sum>>11 & 3]);
	}

	return (u64) v0 + ((u64) v1 << 32);
314
315
}

Miklos Szeredi's avatar
Miklos Szeredi committed
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
/*
 * Check if page is under writeback
 *
 * This is currently done by walking the list of writepage requests
 * for the inode, which can be pretty inefficient.
 */
static bool fuse_page_is_writeback(struct inode *inode, pgoff_t index)
{
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_inode *fi = get_fuse_inode(inode);
	struct fuse_req *req;
	bool found = false;

	spin_lock(&fc->lock);
	list_for_each_entry(req, &fi->writepages, writepages_entry) {
		pgoff_t curr_index;

		BUG_ON(req->inode != inode);
		curr_index = req->misc.write.in.offset >> PAGE_CACHE_SHIFT;
		if (curr_index == index) {
			found = true;
			break;
		}
	}
	spin_unlock(&fc->lock);

	return found;
}

/*
 * Wait for page writeback to be completed.
 *
 * Since fuse doesn't rely on the VM writeback tracking, this has to
 * use some other means.
 */
static int fuse_wait_on_page_writeback(struct inode *inode, pgoff_t index)
{
	struct fuse_inode *fi = get_fuse_inode(inode);

	wait_event(fi->page_waitq, !fuse_page_is_writeback(inode, index));
	return 0;
}

359
static int fuse_flush(struct file *file, fl_owner_t id)
360
{
361
	struct inode *inode = file_inode(file);
362
363
364
365
366
367
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_file *ff = file->private_data;
	struct fuse_req *req;
	struct fuse_flush_in inarg;
	int err;

368
369
370
	if (is_bad_inode(inode))
		return -EIO;

371
372
373
	if (fc->no_flush)
		return 0;

374
	req = fuse_get_req_nofail_nopages(fc, file);
375
376
	memset(&inarg, 0, sizeof(inarg));
	inarg.fh = ff->fh;
377
	inarg.lock_owner = fuse_lock_owner_id(fc, id);
378
379
380
381
382
	req->in.h.opcode = FUSE_FLUSH;
	req->in.h.nodeid = get_node_id(inode);
	req->in.numargs = 1;
	req->in.args[0].size = sizeof(inarg);
	req->in.args[0].value = &inarg;
383
	req->force = 1;
384
	fuse_request_send(fc, req);
385
386
387
388
389
390
391
392
393
	err = req->out.h.error;
	fuse_put_request(fc, req);
	if (err == -ENOSYS) {
		fc->no_flush = 1;
		err = 0;
	}
	return err;
}

Miklos Szeredi's avatar
Miklos Szeredi committed
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
/*
 * Wait for all pending writepages on the inode to finish.
 *
 * This is currently done by blocking further writes with FUSE_NOWRITE
 * and waiting for all sent writes to complete.
 *
 * This must be called under i_mutex, otherwise the FUSE_NOWRITE usage
 * could conflict with truncation.
 */
static void fuse_sync_writes(struct inode *inode)
{
	fuse_set_nowrite(inode);
	fuse_release_nowrite(inode);
}

409
410
int fuse_fsync_common(struct file *file, loff_t start, loff_t end,
		      int datasync, int isdir)
411
{
412
	struct inode *inode = file->f_mapping->host;
413
414
415
416
417
418
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_file *ff = file->private_data;
	struct fuse_req *req;
	struct fuse_fsync_in inarg;
	int err;

419
420
421
	if (is_bad_inode(inode))
		return -EIO;

422
423
424
425
	err = filemap_write_and_wait_range(inode->i_mapping, start, end);
	if (err)
		return err;

426
	if ((!isdir && fc->no_fsync) || (isdir && fc->no_fsyncdir))
427
428
		return 0;

429
430
	mutex_lock(&inode->i_mutex);

Miklos Szeredi's avatar
Miklos Szeredi committed
431
432
433
434
435
436
437
	/*
	 * Start writeback against all dirty pages of the inode, then
	 * wait for all outstanding writes, before sending the FSYNC
	 * request.
	 */
	err = write_inode_now(inode, 0);
	if (err)
438
		goto out;
Miklos Szeredi's avatar
Miklos Szeredi committed
439
440
441

	fuse_sync_writes(inode);

442
	req = fuse_get_req_nopages(fc);
443
444
445
446
	if (IS_ERR(req)) {
		err = PTR_ERR(req);
		goto out;
	}
447
448
449
450

	memset(&inarg, 0, sizeof(inarg));
	inarg.fh = ff->fh;
	inarg.fsync_flags = datasync ? 1 : 0;
451
	req->in.h.opcode = isdir ? FUSE_FSYNCDIR : FUSE_FSYNC;
452
453
454
455
	req->in.h.nodeid = get_node_id(inode);
	req->in.numargs = 1;
	req->in.args[0].size = sizeof(inarg);
	req->in.args[0].value = &inarg;
456
	fuse_request_send(fc, req);
457
458
459
	err = req->out.h.error;
	fuse_put_request(fc, req);
	if (err == -ENOSYS) {
460
461
462
463
		if (isdir)
			fc->no_fsyncdir = 1;
		else
			fc->no_fsync = 1;
464
465
		err = 0;
	}
466
467
out:
	mutex_unlock(&inode->i_mutex);
468
469
470
	return err;
}

471
472
static int fuse_fsync(struct file *file, loff_t start, loff_t end,
		      int datasync)
473
{
474
	return fuse_fsync_common(file, start, end, datasync, 0);
475
476
}

477
478
void fuse_read_fill(struct fuse_req *req, struct file *file, loff_t pos,
		    size_t count, int opcode)
479
{
480
	struct fuse_read_in *inarg = &req->misc.read.in;
481
	struct fuse_file *ff = file->private_data;
482

483
484
485
	inarg->fh = ff->fh;
	inarg->offset = pos;
	inarg->size = count;
486
	inarg->flags = file->f_flags;
487
	req->in.h.opcode = opcode;
488
	req->in.h.nodeid = ff->nodeid;
489
490
	req->in.numargs = 1;
	req->in.args[0].size = sizeof(struct fuse_read_in);
491
	req->in.args[0].value = inarg;
492
493
494
495
496
	req->out.argvar = 1;
	req->out.numargs = 1;
	req->out.args[0].size = count;
}

497
498
499
500
501
502
503
504
505
506
507
508
static void fuse_release_user_pages(struct fuse_req *req, int write)
{
	unsigned i;

	for (i = 0; i < req->num_pages; i++) {
		struct page *page = req->pages[i];
		if (write)
			set_page_dirty_lock(page);
		put_page(page);
	}
}

Maxim Patlasov's avatar
Maxim Patlasov committed
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
/**
 * In case of short read, the caller sets 'pos' to the position of
 * actual end of fuse request in IO request. Otherwise, if bytes_requested
 * == bytes_transferred or rw == WRITE, the caller sets 'pos' to -1.
 *
 * An example:
 * User requested DIO read of 64K. It was splitted into two 32K fuse requests,
 * both submitted asynchronously. The first of them was ACKed by userspace as
 * fully completed (req->out.args[0].size == 32K) resulting in pos == -1. The
 * second request was ACKed as short, e.g. only 1K was read, resulting in
 * pos == 33K.
 *
 * Thus, when all fuse requests are completed, the minimal non-negative 'pos'
 * will be equal to the length of the longest contiguous fragment of
 * transferred data starting from the beginning of IO request.
 */
static void fuse_aio_complete(struct fuse_io_priv *io, int err, ssize_t pos)
{
	int left;

	spin_lock(&io->lock);
	if (err)
		io->err = io->err ? : err;
	else if (pos >= 0 && (io->bytes < 0 || pos < io->bytes))
		io->bytes = pos;

	left = --io->reqs;
	spin_unlock(&io->lock);

	if (!left) {
		long res;

		if (io->err)
			res = io->err;
		else if (io->bytes >= 0 && io->write)
			res = -EIO;
		else {
			res = io->bytes < 0 ? io->size : io->bytes;

			if (!is_sync_kiocb(io->iocb)) {
				struct path *path = &io->iocb->ki_filp->f_path;
				struct inode *inode = path->dentry->d_inode;
				struct fuse_conn *fc = get_fuse_conn(inode);
				struct fuse_inode *fi = get_fuse_inode(inode);

				spin_lock(&fc->lock);
				fi->attr_version = ++fc->attr_version;
				spin_unlock(&fc->lock);
			}
		}

		aio_complete(io->iocb, res, 0);
		kfree(io);
	}
}

static void fuse_aio_complete_req(struct fuse_conn *fc, struct fuse_req *req)
{
	struct fuse_io_priv *io = req->io;
	ssize_t pos = -1;

	fuse_release_user_pages(req, !io->write);

	if (io->write) {
		if (req->misc.write.in.size != req->misc.write.out.size)
			pos = req->misc.write.in.offset - io->offset +
				req->misc.write.out.size;
	} else {
		if (req->misc.read.in.size != req->out.args[0].size)
			pos = req->misc.read.in.offset - io->offset +
				req->out.args[0].size;
	}

	fuse_aio_complete(io, req->out.h.error, pos);
}

static size_t fuse_async_req_send(struct fuse_conn *fc, struct fuse_req *req,
		size_t num_bytes, struct fuse_io_priv *io)
{
	spin_lock(&io->lock);
	io->size += num_bytes;
	io->reqs++;
	spin_unlock(&io->lock);

	req->io = io;
	req->end = fuse_aio_complete_req;

596
	__fuse_get_request(req);
Maxim Patlasov's avatar
Maxim Patlasov committed
597
598
599
600
601
	fuse_request_send_background(fc, req);

	return num_bytes;
}

602
static size_t fuse_send_read(struct fuse_req *req, struct fuse_io_priv *io,
603
			     loff_t pos, size_t count, fl_owner_t owner)
604
{
605
	struct file *file = io->file;
606
607
	struct fuse_file *ff = file->private_data;
	struct fuse_conn *fc = ff->fc;
608

609
	fuse_read_fill(req, file, pos, count, FUSE_READ);
610
	if (owner != NULL) {
611
		struct fuse_read_in *inarg = &req->misc.read.in;
612
613
614
615

		inarg->read_flags |= FUSE_READ_LOCKOWNER;
		inarg->lock_owner = fuse_lock_owner_id(fc, owner);
	}
616
617
618
619

	if (io->async)
		return fuse_async_req_send(fc, req, count, io);

620
	fuse_request_send(fc, req);
621
	return req->out.args[0].size;
622
623
}

624
625
626
627
628
629
630
631
632
633
634
635
636
637
static void fuse_read_update_size(struct inode *inode, loff_t size,
				  u64 attr_ver)
{
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_inode *fi = get_fuse_inode(inode);

	spin_lock(&fc->lock);
	if (attr_ver == fi->attr_version && size < inode->i_size) {
		fi->attr_version = ++fc->attr_version;
		i_size_write(inode, size);
	}
	spin_unlock(&fc->lock);
}

638
639
static int fuse_readpage(struct file *file, struct page *page)
{
640
	struct fuse_io_priv io = { .async = 0, .file = file };
641
642
	struct inode *inode = page->mapping->host;
	struct fuse_conn *fc = get_fuse_conn(inode);
643
	struct fuse_req *req;
644
645
646
647
	size_t num_read;
	loff_t pos = page_offset(page);
	size_t count = PAGE_CACHE_SIZE;
	u64 attr_ver;
648
649
650
651
652
653
	int err;

	err = -EIO;
	if (is_bad_inode(inode))
		goto out;

Miklos Szeredi's avatar
Miklos Szeredi committed
654
	/*
Lucas De Marchi's avatar
Lucas De Marchi committed
655
	 * Page writeback can extend beyond the lifetime of the
Miklos Szeredi's avatar
Miklos Szeredi committed
656
657
658
659
660
	 * page-cache page, so make sure we read a properly synced
	 * page.
	 */
	fuse_wait_on_page_writeback(inode, page->index);

661
	req = fuse_get_req(fc, 1);
662
663
	err = PTR_ERR(req);
	if (IS_ERR(req))
664
665
		goto out;

666
667
	attr_ver = fuse_get_attr_version(fc);

668
	req->out.page_zeroing = 1;
669
	req->out.argpages = 1;
670
671
	req->num_pages = 1;
	req->pages[0] = page;
672
	req->page_descs[0].length = count;
673
	num_read = fuse_send_read(req, &io, pos, count, NULL);
674
675
	err = req->out.h.error;
	fuse_put_request(fc, req);
676
677
678
679
680
681
682
683

	if (!err) {
		/*
		 * Short read means EOF.  If file size is larger, truncate it
		 */
		if (num_read < count)
			fuse_read_update_size(inode, pos + num_read, attr_ver);

684
		SetPageUptodate(page);
685
686
	}

687
	fuse_invalidate_attr(inode); /* atime changed */
688
689
690
691
692
 out:
	unlock_page(page);
	return err;
}

693
static void fuse_readpages_end(struct fuse_conn *fc, struct fuse_req *req)
694
{
695
	int i;
696
697
	size_t count = req->misc.read.in.size;
	size_t num_read = req->out.args[0].size;
698
	struct address_space *mapping = NULL;
699

700
701
	for (i = 0; mapping == NULL && i < req->num_pages; i++)
		mapping = req->pages[i]->mapping;
702

703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
	if (mapping) {
		struct inode *inode = mapping->host;

		/*
		 * Short read means EOF. If file size is larger, truncate it
		 */
		if (!req->out.h.error && num_read < count) {
			loff_t pos;

			pos = page_offset(req->pages[0]) + num_read;
			fuse_read_update_size(inode, pos,
					      req->misc.read.attr_ver);
		}
		fuse_invalidate_attr(inode); /* atime changed */
	}
718

719
720
721
722
	for (i = 0; i < req->num_pages; i++) {
		struct page *page = req->pages[i];
		if (!req->out.h.error)
			SetPageUptodate(page);
723
724
		else
			SetPageError(page);
725
		unlock_page(page);
726
		page_cache_release(page);
727
	}
728
	if (req->ff)
729
		fuse_file_put(req->ff, false);
730
731
}

732
static void fuse_send_readpages(struct fuse_req *req, struct file *file)
733
{
734
735
	struct fuse_file *ff = file->private_data;
	struct fuse_conn *fc = ff->fc;
736
737
	loff_t pos = page_offset(req->pages[0]);
	size_t count = req->num_pages << PAGE_CACHE_SHIFT;
738
739

	req->out.argpages = 1;
740
	req->out.page_zeroing = 1;
741
	req->out.page_replace = 1;
742
	fuse_read_fill(req, file, pos, count, FUSE_READ);
743
	req->misc.read.attr_ver = fuse_get_attr_version(fc);
744
	if (fc->async_read) {
745
		req->ff = fuse_file_get(ff);
746
		req->end = fuse_readpages_end;
747
		fuse_request_send_background(fc, req);
748
	} else {
749
		fuse_request_send(fc, req);
750
		fuse_readpages_end(fc, req);
751
		fuse_put_request(fc, req);
752
	}
753
754
}

755
struct fuse_fill_data {
756
	struct fuse_req *req;
757
	struct file *file;
758
	struct inode *inode;
Maxim Patlasov's avatar
Maxim Patlasov committed
759
	unsigned nr_pages;
760
761
762
763
};

static int fuse_readpages_fill(void *_data, struct page *page)
{
764
	struct fuse_fill_data *data = _data;
765
766
767
768
	struct fuse_req *req = data->req;
	struct inode *inode = data->inode;
	struct fuse_conn *fc = get_fuse_conn(inode);

Miklos Szeredi's avatar
Miklos Szeredi committed
769
770
	fuse_wait_on_page_writeback(inode, page->index);

771
772
773
774
	if (req->num_pages &&
	    (req->num_pages == FUSE_MAX_PAGES_PER_REQ ||
	     (req->num_pages + 1) * PAGE_CACHE_SIZE > fc->max_read ||
	     req->pages[req->num_pages - 1]->index + 1 != page->index)) {
Maxim Patlasov's avatar
Maxim Patlasov committed
775
776
		int nr_alloc = min_t(unsigned, data->nr_pages,
				     FUSE_MAX_PAGES_PER_REQ);
777
		fuse_send_readpages(req, data->file);
778
779
780
781
782
783
		if (fc->async_read)
			req = fuse_get_req_for_background(fc, nr_alloc);
		else
			req = fuse_get_req(fc, nr_alloc);

		data->req = req;
784
		if (IS_ERR(req)) {
785
			unlock_page(page);
786
			return PTR_ERR(req);
787
788
		}
	}
Maxim Patlasov's avatar
Maxim Patlasov committed
789
790
791
792
793
794

	if (WARN_ON(req->num_pages >= req->max_pages)) {
		fuse_put_request(fc, req);
		return -EIO;
	}

795
	page_cache_get(page);
796
	req->pages[req->num_pages] = page;
797
	req->page_descs[req->num_pages].length = PAGE_SIZE;
Miklos Szeredi's avatar
Miklos Szeredi committed
798
	req->num_pages++;
Maxim Patlasov's avatar
Maxim Patlasov committed
799
	data->nr_pages--;
800
801
802
803
804
805
806
807
	return 0;
}

static int fuse_readpages(struct file *file, struct address_space *mapping,
			  struct list_head *pages, unsigned nr_pages)
{
	struct inode *inode = mapping->host;
	struct fuse_conn *fc = get_fuse_conn(inode);
808
	struct fuse_fill_data data;
809
	int err;
Maxim Patlasov's avatar
Maxim Patlasov committed
810
	int nr_alloc = min_t(unsigned, nr_pages, FUSE_MAX_PAGES_PER_REQ);
811

812
	err = -EIO;
813
	if (is_bad_inode(inode))
814
		goto out;
815

816
	data.file = file;
817
	data.inode = inode;
818
819
820
821
	if (fc->async_read)
		data.req = fuse_get_req_for_background(fc, nr_alloc);
	else
		data.req = fuse_get_req(fc, nr_alloc);
Maxim Patlasov's avatar
Maxim Patlasov committed
822
	data.nr_pages = nr_pages;
823
	err = PTR_ERR(data.req);
824
	if (IS_ERR(data.req))
825
		goto out;
826
827

	err = read_cache_pages(mapping, pages, fuse_readpages_fill, &data);
828
829
	if (!err) {
		if (data.req->num_pages)
830
			fuse_send_readpages(data.req, file);
831
832
833
		else
			fuse_put_request(fc, data.req);
	}
834
out:
835
	return err;
836
837
}

Miklos Szeredi's avatar
Miklos Szeredi committed
838
839
840
841
static ssize_t fuse_file_aio_read(struct kiocb *iocb, const struct iovec *iov,
				  unsigned long nr_segs, loff_t pos)
{
	struct inode *inode = iocb->ki_filp->f_mapping->host;
842
	struct fuse_conn *fc = get_fuse_conn(inode);
Miklos Szeredi's avatar
Miklos Szeredi committed
843

844
845
846
847
848
849
850
	/*
	 * In auto invalidate mode, always update attributes on read.
	 * Otherwise, only update if we attempt to read past EOF (to ensure
	 * i_size is up to date).
	 */
	if (fc->auto_inval_data ||
	    (pos + iov_length(iov, nr_segs) > i_size_read(inode))) {
Miklos Szeredi's avatar
Miklos Szeredi committed
851
852
853
854
855
856
857
858
859
		int err;
		err = fuse_update_attributes(inode, NULL, iocb->ki_filp, NULL);
		if (err)
			return err;
	}

	return generic_file_aio_read(iocb, iov, nr_segs, pos);
}

860
static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
861
			    loff_t pos, size_t count)
862
{
863
864
	struct fuse_write_in *inarg = &req->misc.write.in;
	struct fuse_write_out *outarg = &req->misc.write.out;
865

866
867
868
	inarg->fh = ff->fh;
	inarg->offset = pos;
	inarg->size = count;
869
	req->in.h.opcode = FUSE_WRITE;
870
	req->in.h.nodeid = ff->nodeid;
871
	req->in.numargs = 2;
872
	if (ff->fc->minor < 9)
873
874
875
		req->in.args[0].size = FUSE_COMPAT_WRITE_IN_SIZE;
	else
		req->in.args[0].size = sizeof(struct fuse_write_in);
876
	req->in.args[0].value = inarg;
877
878
879
	req->in.args[1].size = count;
	req->out.numargs = 1;
	req->out.args[0].size = sizeof(struct fuse_write_out);
880
881
882
	req->out.args[0].value = outarg;
}

883
static size_t fuse_send_write(struct fuse_req *req, struct fuse_io_priv *io,
884
			      loff_t pos, size_t count, fl_owner_t owner)
885
{
886
	struct file *file = io->file;
887
888
	struct fuse_file *ff = file->private_data;
	struct fuse_conn *fc = ff->fc;
889
890
	struct fuse_write_in *inarg = &req->misc.write.in;

891
	fuse_write_fill(req, ff, pos, count);
892
	inarg->flags = file->f_flags;
893
894
895
896
	if (owner != NULL) {
		inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
		inarg->lock_owner = fuse_lock_owner_id(fc, owner);
	}
897
898
899
900

	if (io->async)
		return fuse_async_req_send(fc, req, count, io);

901
	fuse_request_send(fc, req);
902
	return req->misc.write.out.size;
903
904
}

Miklos Szeredi's avatar
Miklos Szeredi committed
905
void fuse_write_update_size(struct inode *inode, loff_t pos)
906
907
908
909
910
911
912
913
914
915
916
{
	struct fuse_conn *fc = get_fuse_conn(inode);
	struct fuse_inode *fi = get_fuse_inode(inode);

	spin_lock(&fc->lock);
	fi->attr_version = ++fc->attr_version;
	if (pos > inode->i_size)
		i_size_write(inode, pos);
	spin_unlock(&fc->lock);
}

Nick Piggin's avatar
Nick Piggin committed
917
918
919
920
921
922
923
static size_t fuse_send_write_pages(struct fuse_req *req, struct file *file,
				    struct inode *inode, loff_t pos,
				    size_t count)
{
	size_t res;
	unsigned offset;
	unsigned i;
924
	struct fuse_io_priv io = { .async = 0, .file = file };
Nick Piggin's avatar
Nick Piggin committed
925
926
927
928

	for (i = 0; i < req->num_pages; i++)
		fuse_wait_on_page_writeback(inode, req->pages[i]->index);

929
	res = fuse_send_write(req, &io, pos, count, NULL);
Nick Piggin's avatar
Nick Piggin committed
930

931
	offset = req->page_descs[0].offset;
Nick Piggin's avatar
Nick Piggin committed
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
	count = res;
	for (i = 0; i < req->num_pages; i++) {
		struct page *page = req->pages[i];

		if (!req->out.h.error && !offset && count >= PAGE_CACHE_SIZE)
			SetPageUptodate(page);

		if (count > PAGE_CACHE_SIZE - offset)
			count -= PAGE_CACHE_SIZE - offset;
		else
			count = 0;
		offset = 0;

		unlock_page(page);
		page_cache_release(page);
	}

	return res;
}

static ssize_t fuse_fill_write_pages(struct fuse_req *req,
			       struct address_space *mapping,
			       struct iov_iter *ii, loff_t pos)
{
	struct fuse_conn *fc = get_fuse_conn(mapping->host);
	unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
	size_t count = 0;
	int err;

961
	req->in.argpages = 1;
962
	req->page_descs[0].offset = offset;
Nick Piggin's avatar
Nick Piggin committed
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978

	do {
		size_t tmp;
		struct page *page;
		pgoff_t index = pos >> PAGE_CACHE_SHIFT;
		size_t bytes = min_t(size_t, PAGE_CACHE_SIZE - offset,
				     iov_iter_count(ii));

		bytes = min_t(size_t, bytes, fc->max_write - count);

 again:
		err = -EFAULT;
		if (iov_iter_fault_in_readable(ii, bytes))
			break;

		err = -ENOMEM;
979
		page = grab_cache_page_write_begin(mapping, index, 0);
Nick Piggin's avatar
Nick Piggin committed
980
981
982
		if (!page)
			break;

983
984
985
		if (mapping_writably_mapped(mapping))
			flush_dcache_page(page);

Nick Piggin's avatar
Nick Piggin committed
986
987
988
989
990
		pagefault_disable();
		tmp = iov_iter_copy_from_user_atomic(page, ii, offset, bytes);
		pagefault_enable();
		flush_dcache_page(page);

991
992
		mark_page_accessed(page);

Nick Piggin's avatar
Nick Piggin committed
993
994
995
996
997
998
999
1000
1001
		if (!tmp) {
			unlock_page(page);
			page_cache_release(page);
			bytes = min(bytes, iov_iter_single_seg_count(ii));
			goto again;
		}

		err = 0;
		req->pages[req->num_pages] = page;
1002
		req->page_descs[req->num_pages].length = tmp;
Nick Piggin's avatar
Nick Piggin committed
1003
1004
1005
1006
1007
1008
1009
1010
1011
		req->num_pages++;

		iov_iter_advance(ii, tmp);
		count += tmp;
		pos += tmp;
		offset += tmp;
		if (offset == PAGE_CACHE_SIZE)
			offset = 0;

1012
1013
		if (!fc->big_writes)
			break;
Nick Piggin's avatar
Nick Piggin committed
1014
	} while (iov_iter_count(ii) && count < fc->max_write &&
1015
		 req->num_pages < req->max_pages && offset == 0);
Nick Piggin's avatar
Nick Piggin committed
1016
1017
1018
1019

	return count > 0 ? count : err;
}

1020
1021
1022
1023
1024
1025
1026
1027
static inline unsigned fuse_wr_pages(loff_t pos, size_t len)
{
	return min_t(unsigned,
		     ((pos + len - 1) >> PAGE_CACHE_SHIFT) -
		     (pos >> PAGE_CACHE_SHIFT) + 1,
		     FUSE_MAX_PAGES_PER_REQ);
}

Nick Piggin's avatar
Nick Piggin committed
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
static ssize_t fuse_perform_write(struct file *file,
				  struct address_space *mapping,
				  struct iov_iter *ii, loff_t pos)
{
	struct inode *inode = mapping->host;
	struct fuse_conn *fc = get_fuse_conn(inode);
	int err = 0;
	ssize_t res = 0;

	if (is_bad_inode(inode))
		return -EIO;

	do {
		struct fuse_req *req;
		ssize_t count;
1043
		unsigned nr_pages = fuse_wr_pages(pos, iov_iter_count(ii));
Nick Piggin's avatar
Nick Piggin committed
1044

1045
		req = fuse_get_req(fc, nr_pages);
Nick Piggin's avatar
Nick Piggin committed
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
		if (IS_ERR(req)) {
			err = PTR_ERR(req);
			break;
		}

		count = fuse_fill_write_pages(req, mapping, ii, pos);
		if (count <= 0) {
			err = count;
		} else {
			size_t num_written;

			num_written = fuse_send_write_pages(req, file, inode,
							    pos, count);
			err = req->out.h.error;
			if (!err) {
				res += num_written;
				pos += num_written;

				/* break out of the loop on short write */
				if (num_written != count)
					err = -EIO;
			}
		}
		fuse_put_request(fc, req);
	} while (!err && iov_iter_count(ii));

	if (res > 0)
		fuse_write_update_size(inode, pos);

	fuse_invalidate_attr(inode);

	return res > 0 ? res : err;
}

static ssize_t fuse_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
				   unsigned long nr_segs, loff_t pos)
{
	struct file *file = iocb->ki_filp;
	struct address_space *mapping = file->f_mapping;
	size_t count = 0;
Anand Avati's avatar
Anand Avati committed
1086
	size_t ocount = 0;
Nick Piggin's avatar
Nick Piggin committed
1087
	ssize_t written = 0;
Anand Avati's avatar
Anand Avati committed
1088
	ssize_t written_buffered = 0;
Nick Piggin's avatar
Nick Piggin committed
1089
1090
1091
	struct inode *inode = mapping->host;
	ssize_t err;
	struct iov_iter i;
Anand Avati's avatar
Anand Avati committed
1092
	loff_t endbyte = 0;
Nick Piggin's avatar
Nick Piggin committed
1093
1094
1095

	WARN_ON(iocb->ki_pos != pos);

Anand Avati's avatar
Anand Avati committed
1096
1097
	ocount = 0;
	err = generic_segment_checks(iov, &nr_segs, &ocount, VERIFY_READ);
Nick Piggin's avatar
Nick Piggin committed
1098
1099
1100
	if (err)
		return err;

Anand Avati's avatar
Anand Avati committed
1101
	count = ocount;
1102
	sb_start_write(inode->i_sb);
Nick Piggin's avatar
Nick Piggin committed
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
	mutex_lock(&inode->i_mutex);

	/* We can write back this queue in page reclaim */
	current->backing_dev_info = mapping->backing_dev_info;

	err = generic_write_checks(file, &pos, &count, S_ISBLK(inode->i_mode));
	if (err)
		goto out;

	if (count == 0)
		goto out;

1115
	err = file_remove_suid(file);
Nick Piggin's avatar
Nick Piggin committed
1116
1117
1118
	if (err)
		goto out;

1119
1120
1121
	err = file_update_time(file);
	if (err)
		goto out;
Nick Piggin's avatar
Nick Piggin committed
1122

Anand Avati's avatar
Anand Avati committed
1123
1124
1125
1126
1127
1128
1129
1130
1131
	if (file->f_flags & O_DIRECT) {
		written = generic_file_direct_write(iocb, iov, &nr_segs,
						    pos, &iocb->ki_pos,
						    count, ocount);
		if (written < 0 || written == count)
			goto out;

		pos += written;
		count -= written;
Nick Piggin's avatar
Nick Piggin committed
1132

Anand Avati's avatar
Anand Avati committed
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
		iov_iter_init(&i, iov, nr_segs, count, written);
		written_buffered = fuse_perform_write(file, mapping, &i, pos);
		if (written_buffered < 0) {
			err = written_buffered;
			goto out;
		}
		endbyte = pos + written_buffered - 1;

		err = filemap_write_and_wait_range(file->f_mapping, pos,
						   endbyte);
		if (err)
			goto out;

		invalidate_mapping_pages(file->f_mapping,
					 pos >> PAGE_CACHE_SHIFT,
					 endbyte >> PAGE_CACHE_SHIFT);

		written += written_buffered;
		iocb->ki_pos = pos + written_buffered;
	} else {
		iov_iter_init(&i, iov, nr_segs, count, 0);
		written = fuse_perform_write(file, mapping, &i, pos);
		if (written >= 0)
			iocb->ki_pos = pos + written;
	}
Nick Piggin's avatar
Nick Piggin committed
1158
1159
1160
out:
	current->backing_dev_info = NULL;
	mutex_unlock(&inode->i_mutex);
1161
	sb_end_write(inode->i_sb);
Nick Piggin's avatar
Nick Piggin committed
1162
1163
1164
1165

	return written ? written : err;
}

1166
1167
static inline void fuse_page_descs_length_init(struct fuse_req *req,
		unsigned index, unsigned nr_pages)
1168
1169
1170
{
	int i;

1171
	for (i = index; i < index + nr_pages; i++)
1172
1173
1174
1175
		req->page_descs[i].length = PAGE_SIZE -
			req->page_descs[i].offset;
}

1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
static inline unsigned long fuse_get_user_addr(const struct iov_iter *ii)
{
	return (unsigned long)ii->iov->iov_base + ii->iov_offset;
}

static inline size_t fuse_get_frag_size(const struct iov_iter *ii,
					size_t max_size)
{
	return min(iov_iter_single_seg_count(ii), max_size);
}

1187
static int fuse_get_user_pages(struct fuse_req *req, struct iov_iter *ii,
1188
			       size_t *nbytesp, int write)
Miklos Szeredi's avatar
Miklos Szeredi committed
1189
{
1190
	size_t nbytes = 0;  /* # bytes already packed in req */
1191

1192
1193
	/* Special case for kernel I/O: can copy directly into the buffer */
	if (segment_eq(get_fs(), KERNEL_DS)) {
1194
1195
1196
		unsigned long user_addr = fuse_get_user_addr(ii);
		size_t frag_size = fuse_get_frag_size(ii, *nbytesp);

1197
1198
1199
1200
1201
		if (write)
			req->in.args[1].value = (void *) user_addr;
		else
			req->out.args[0].value = (void *) user_addr;

1202
1203
		iov_iter_advance<